The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial Multicenter Study Comparative Study
Safety and efficacy of once-daily hydromorphone extended-release versus twice-daily oxycodone hydrochloride controlled-release in chinese patients with cancer pain: a phase 3, randomized, double-blind, multicenter study.
Noninferiority of the efficacy of once-daily hydromorphone hydrochloride extended-release (hydromorphone ER) compared with twice-daily oxycodone hydrochloride controlled-release (oxycodone CR) was investigated in this randomized, double-blind study in Chinese patients with moderate to severe cancer pain requiring strong oral opioid analgesics. Randomization (1:1) to hydromorphone ER (8-32 mg) or oxycodone CR (10-40 mg) was followed by dose titration (up to 8 days) and dose maintenance (28 days, weekly visits). Primary endpoint was change from baseline to end of study in "worst pain in the past 24 hours" of Brief Pain Inventory (Short Form) score on last observation carried forward (per protocol set). A total of 137 of 260 randomized patients completed maintenance phase (hydromorphone ER: n = 70; oxycodone CR: n = 67); per protocol set: 81 patients. Mean age was 53.1 years (range: 18-70 years; males: 65.3%); most common Eastern Cooperative Oncology Group performance status = 2. Least square mean difference between 2 treatment groups for primary endpoint using analysis of covariance (baseline score, covariate) was -.1 (95% confidence interval: -1.3, 1.1), with upper bound of 95% confidence interval <1.5 (predefined noninferiority margin). Most common reason for deaths was disease progression (hydromorphone ER: 6.3%; oxycodone CR: 12.7%). Treatment-emergent adverse events were comparable between treatment groups. Hydromorphone ER was noninferior to oxycodone CR in alleviating cancer pain and was well tolerated. ⋯ This article demonstrates clinical noninferiority of the efficacy of once-daily hydromorphone ER compared with twice-daily oxycodone CR in alleviating cancer pain in Chinese patients, with comparable safety profiles between the 2 treatment groups. Thus, a treatment option with the potential for a reduced dosing frequency exists for health care providers and patients.
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The insular cortex (IC) and cingulate cortex (CC) are critically involved in pain perception. Previously we demonstrated that fibromyalgia (FM) patients have greater connectivity between the insula and default mode network at rest, and that changes in the degree of this connectivity were associated with changes in the intensity of ongoing clinical pain. In this study we more thoroughly evaluated the degree of resting-state connectivity to multiple regions of the IC in individuals with FM and healthy controls. We also investigated the relationship between connectivity, experimental pain, and current clinical chronic pain. Functional connectivity was assessed using resting-state functional magnetic resonance imaging in 18 FM patients and 18 age- and sex-matched healthy controls using predefined seed regions in the anterior, middle, and posterior IC. FM patients exhibited greater connectivity between 1) right mid IC and right mid/posterior CC and right mid IC, 2) right posterior IC and left CC, and 3) right anterior IC and left superior temporal gyrus. Healthy controls displayed greater connectivity between left anterior IC and bilateral medial frontal gyrus/anterior cingulate cortex; and left posterior IC and right superior frontal gyrus. Within the FM group, greater connectivity between the IC and CC was associated with decreased pressure-pain thresholds. ⋯ These data provide further support for altered resting-state connectivity between the IC and other brain regions known to participate in pain perception/modulation, which may play a pathogenic role in conditions such as FM. We speculate that altered IC connectivity is associated with the experience of chronic pain in individuals with FM.
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This paper tests the contribution of the toll-like receptors, TLR4 in particular, in the initiation and maintenance of paclitaxel-related chemotherapy-induced peripheral neuropathy. TLR4 and its immediate downstream signaling molecules-myeloid differentiation primary response gene 88 (MyD88) and toll/interleukin 1 receptor domain-containing adapter-inducing interferon-β (TRIF)-were found to be increased in the dorsal root ganglion (DRG) using Western blot by day 7 of paclitaxel treatment. The behavioral phenotype, the increase of both TLR4 and MyD88, was blocked by cotreatment with the TLR4 antagonist lipopolysaccharide-Rhodobacter sphaeroides during chemotherapy. A similar, but less robust, behavioral effect was observed using intrathecal treatment of MyD88 homodimerization inhibitory peptide. DRG levels of TLR4 and MyD88 reduced over the next 2 weeks, whereas these levels remained increased in spinal cord through day 21 following chemotherapy. Immunohistochemical analysis revealed TLR4 expression in both calcitonin gene-related peptide-positive and isolectin B4-positive small DRG neurons. MyD88 was only found in calcitonin gene-related peptide-positive neurons, and TRIF was found in both calcitonin gene-related peptide-positive and isolectin B4-positive small DRG neurons as well as in medium- and large-size DRG neurons. In the spinal cord, TLR4 was only found colocalized to astrocytes but not with either microglia or neurons. Intrathecal treatment with the TLR4 antagonist lipopolysaccharide-R. sphaeroides transiently reversed preestablished chemotherapy-induced peripheral neuropathy mechanical hypersensitivity. These results strongly implicate TLR4 signaling in the DRG and the spinal cord in the induction and maintenance of paclitaxel-related chemotherapy-induced peripheral neuropathy. ⋯ The toll-like receptor TLR4 and MyD88 signaling pathway could be a new potential therapeutic target in paclitaxel-induced painful neuropathy.
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Chronic pain is a major symptom in patients with endometriosis, a common gynecologic condition affecting women in their reproductive years. Although many proalgesic substances are produced by endometriosis lesions, experimental evidence supporting their relative roles is still lacking. Furthermore, it is unclear whether these proalgesic agents directly activate nociceptors to induce endometriosis pain. To determine their relative contribution to pain associated with endometriosis, we evaluated the intrathecal administration of oligodeoxynucleotides (ODNs) antisense to messenger RNA for receptors for 3 pronociceptive mediators known to be produced by the ectopic endometrium. Two weeks after the implant of autologous uterine tissue onto the gastrocnemius muscle, local mechanical hyperalgesia was observed in operated rats. Intrathecal antisense ODN targeting messenger RNA for the interleukin 6 receptor-signaling complex subunit glycoprotein 130 and the nerve growth factor tyrosine kinase receptor A, but not their mismatch ODNs, reversibly attenuated mechanical hyperalgesia at the implant site. In contrast, intrathecal antisense ODN targeting the tumor necrosis factor receptor 1, at a dose that markedly inhibited intramuscularly injected tumor necrosis factor alpha, had only a small antihyperalgesic effect in this model. These results indicate the relative contribution of pronociceptive mediators produced by ectopic endometrial tissue to endometriosis pain. The experimental approach presented here provides a novel method to evaluate for the differential contribution of mediators produced by other painful lesions as well as endometriosis lesions as targets for novel treatment of pain syndromes. ⋯ This article presents evidence for the relative contribution of proalgesic mediators to primary hyperalgesia displayed by rats submitted to a model of endometriosis pain. This approach can be used to identify potential targets for the treatment of endometriosis pain.